1. Field of the Invention
The subject invention relates generally to fire simulation systems for training municipal, military, and other firefighter trainees as to the preferred procedures for suppressing and ultimately extinguishing fires. More particularly, the invention relates to a firefighter training system which is operable to produce a more realistic live fire simulation of fuel spill, chemical and similar types of fires, as well as to enhance system reliability by reducing system operating temperatures during and immediately following the conducting of a training scenario.
2. Description of the Related Art
Conventional firefighter training practices typically provide for the combustion of flammable materials, such as wood, straw, and other organic and inorganic materials, which are to be extinguished by the trainee upon the application thereon of sufficient quantities of an appropriate extinguishing agent. The extinguishing agent that is most commonly utilized is water, due principally to its availability, cost and widespread usage as a fire extinguishing material. However, these conventional training practices have come under scrutiny in recent years as a result of the relatively high injury rate, adverse environmental impact, and limited training effectiveness and trainee throughput that is associated with such practices. For example, the National Fire Protection Association (NFPA) reports that in the United States alone, nearly 6,000 training-related injuries were sustained by firefighters in 1988. Nevertheless, live fire training is a crucial and necessary component of firefighter training, for it most closely represents the overall environment a firefighter is likely to encounter during a genuine fire emergency. Unfortunately, conventional live fires that are set for the purpose of firefighter trainee education suffer from many of the very same hazards that are associated with genuine fire emergencies--unpredictability of fire propagation and its response to firefighter suppression tactics. As a consequence of these characteristics, it is oftentimes necessary for the trainee supervisors to themselves suppress the live fire prior to rendering perhaps life-saying assistance to a fallen trainee. Furthermore, because the very nature of a conventional live fire is unpredictability, it is not possible to accurately and readily reproduce a desired fire condition for a succession of firefighter trainees.
In an effort to address the foregoing deficiencies in firefighter training, live fire simulator systems have been implemented since the early 1970's which provide for, among other features, the substitution of various controllable arrangements of propane and natural gas-operable burners located within dedicated "burn rooms" for the prior practice of igniting various flammable props (i.e., wood or straw bundles) or even buildings to be razed. Illustrative of the newer generation of live firefighter training simulators is that disclosed in U.S. Pat. No. 4,303,396 and assigned to the United States of America as represented by the Secretary of the Navy. The simulator disclosed in this referenced patent, which is hereby incorporated by reference, provides a plurality of chambers, each of which can be provided with a fire from a fuel burner that is representative of a variety of different types of fires. This simulator is useful in educating firefighter trainees as to some general principles of fire extinguishment, such as spray nozzle control and various extinguishing agent application techniques. However, because a solid floor is used, applied extinguishing agent collects on the floor and poses a hazard to firefighter personnel due to slippage. Moreover, because a solid floor surface is provided, it is not possible to simulate fuel spill and similar types of floor level fires, as the burners are mounted above the floor on a platform. Accordingly, the disclosed trainer is not capable of rendering a realistic fuel spill-type of fire of the kind that firefighters can regularly be expected to encounter on board ocean going surface and sub-surface vessels, at petroleum refineries and chemical plants, municipal and military airports, and the like.
The United States Navy has commissioned several contractors to construct a surface vessel trainer that is operable to simulate fuel spill fires and the like. This trainer, known as the Device 19F4 Trainer, Basic Fire Fighting Aircraft, includes a number of gaseous propane-fueled burners that are mounted below a metal floor grating. The burners are operable to generate a live fire having flames that pass upward through the grating. Firefighter personnel apply water or foam extinguishing agents and advance along a path over the grating through which the flames pass as they suppress the fire. The gratings are typically 1.25 in. thick A36, stainless or other suitable grade of steel.
A number of critical operational, safety and simulation deficiencies have developed from use of the Device 19F4 trainer. Because the flames pass through the metal grating, the grating can heat to temperatures in excess of 850.degree. F., at which temperature the grating can glow red hot and radiate considerable amounts of heat, posing a serious safety hazard to firefighter personnel. As extinguishing agent is applied to the fire, the grating is subjected to considerable thermal stress resulting from the rapid cooling effects of the extinguishing agent. As a consequence of this thermal stress, a problem has been experienced with grating warpage and/or cracking, necessitating replacement of the gratings well in advance of their originally-projected service life. As the gratings are quite expensive, the overall cost associated with system operation increases significantly. Further, grating warpage poses a safety hazard to firefighter personnel who, because of limited visibility during the training scenario due to the wearing of self contained breathing apparatus ("SCBA") gear, the generation of vapor from agent application to the heated grating and artificial smoke that is oftentimes introduced to enhance realism of the training scenario, can trip and fall onto the gratings and incur severe burns. Additionally, the grating does not provide for a realistic simulation of a fuel spill, chemical and similar fires of the type that can occur on board Naval vessels, as the flames do not collect and pool as they do in genuine fire emergencies on board ship.
The foregoing and other deficiencies are overcome by the new methods and apparatus of the present invention, the details of which are set forth in the following text and accompanying claims.